In recent years, semiconductor integrated circuits have been increasingly microfabricated and integrated. In order to achieve such a microfabrication process, photolithography devices have been developed as a pattern transferring technique to have a higher degree of accuracy. However, the microfabrication process has approached the wavelength of a light source of an exposure device, and thus the photolithography technique has also been approaching its limit. Thus, an electron-beam drawing device, which is a type of charged particle beam equipment, has come into use to further promote microfabrication and enhance the accuracy, in place of the photolithography technique.
Patterning using electron beams involves drawing a mask pattern, unlike one-shot exposure method in patterning using a light source, such as an i-line or an excimer laser. Thus, the larger the number of patterns to be drawn, the longer the exposure (drawing) time, which disadvantageously takes a considerable time for patterning. For this reason, a dramatic rise in the degree of integration to, in turn, 256 megabits, 1 gigabit, and 4 gigabits causes a correspondingly dramatic increase in patterning time, which may lead to large degradation in throughput. A collective figure irradiation method has been developed which involves collectively irradiating a combination of masks having various shapes with electron beams at a time, thereby yielding electron beams in complicated form so as to speed up the electron beam drawing device. As a result, the microfabrication of the pattern has been promoted, while the electron beam drawing device has to be upsized, but a mechanism for more accurately controlling the positions of the masks is required, which results in high cost of the device.
On the other hand, techniques for forming the fine patterns at low cost are disclosed in, for example, U.S. Pat. No. 5,772,905 and JP-A-03-230334. Those techniques involve pressing a mold having the same concave-convex pattern as that to be formed on an imprinting object against a resist film layer formed on a surface of an imprinting substrate, thereby imprinting the predetermined pattern onto the resist layer. In particular, a nanoimprint technique as described in U.S. Pat. No. 5,772,905 can form a fine structure having a size of 25 nanometers or less by imprinting using a silicon wafer as a mold.
The imprinting method as disclosed in U.S. Pat. No. 5,772,905 involves putting a mold on a substrate coated with resin, mounting the substrate and the mold on a stage of a parallel flat plate type press device which enables heating and pressurizing, heating the substrate and the mold at a temperature equal to or more than a glass transition temperature of the resin, and then pressurizing them. The imprinting method further involves cooling the substrate and the mold down to a temperature equal to or less than the glass transition temperature, and separating the mold from the substrate thereby to perform imprinting of the pattern.
Further, JP-A-03-230334 discloses a method for imprinting a pattern by means of a heating and pressurizing roller while conveying a continuous film-like substrate. The patent document has reported that the method suppresses deformation of the pattern on the substrate, thereby surely enabling the imprinting of the concave-convex pattern.
However, the method disclosed in U.S. Pat. No. 5,772,905 takes long time to perform one-time imprinting because imprinting of the pattern onto the substrate needs processes of heating, pressurizing, cooling, and separating in turn, which makes it difficult to produce fine structures in quantity. On the other hand, the method disclosed in JP-A-03-230334, which involves imprinting the pattern by the heating and pressurizing roller while conveying the continuous film-like substrate, can continuously imprint the pattern onto the imprinting object. The method can be expected to perform the imprinting over a large area at high throughput. The inventors have tried the method disclosed in JP-A-03-230334 to imprint a pattern onto a thin film-like substrate, but have apparently found that wrinkled traces occurred in the object subjected to imprinting.